Why do I get the urge to break something when I am angry?

People usually get angry in response to feelings of vulnerability and disempowerment. Any situation where someone gets angry, they are also probably feeling something like hurt, insecure, disrespected, invalidated, betrayed, frustrated, threatened, the list goes on. Anger allows you to get some of that power back and direct those negative feelings outward on to someone/something else. It often makes people feel better in the short term, even though there are typically long term consequences of acting aggressively.